The objectives of my proposed research are: 1. To detect and identify several tumor-specific antigens from chemically induced sarcomas in mice. 2. To purify those tumor antigens which are found in sufficient quantities. 3. To determine the molecular nature of purified tumor antigens including their molecular weights, amino acid and carbohydrate compositions, and primary structures. 4. To ascertain from these results whether or not there exists any evolutionary relationship among different tumor antigens. The methods that will be used in this study will include radioactive labeling (either biosynthetically or with 125I) of cell surface antigens, electrophoresis of material on polyacrylamide gels in the presence of sodium dodecyl sulfate and autoradiography to record the electrophoresis patterns. Antigen purification will be achieved whenever possible by immunoadsorption methods. Recent advances in microanalysis in protein chemistry make it feasible at this time to attempt to determine many of the physical and chemical properties of macromolecules obtainable only in small quantities.